Venetian blinds



Jan. 12, 1960 J. F. BENNETT VENETIAN BLINDS 2 Sheets-Sheet 1 Filed Dec. 22, 1958 Jan. 12, 1960 J. F. BENNETT VENETIAN BLINDS 2 Sheets-Sheet 2 Filed Dec. 22, 1958 VENETIAN BLINDS Jack Franklin Bennett, Kingswood, England Application December 22, 1958, Serial No. 782,122

9 Claims. (Cl. 160-167) This invention relates to Venetian blinds, and its general object is to provide a blind in which the vertical expanse of the area covered by the blind can be varied by varying the height of both the bottom and the top of the slat assembly, in which the degree of obturation of light by the slat assembly can be varied by tilting the slats about their lengthwise axes, and in which any one of these three motions can be effected without effecting either of the other two motions.

A further object is to provide a Venetian blind in which the slats can be lowered to convenient heights for cleaning and in which the slat assembly can be so positioned as to obstruct the passage of light and air through any selected horizontal section of a window or other opening, while at the same time permitting the free passage of light and air both above and below that section.

Another object is to provide a Venetian blind capable of performing the above-mentioned functions which is simple in construction, inexpensive in manufacture, efficient in operation, and durable in service.

A further object of the invention is to provide a Venetian blind in which the cords which are used for tilting the slats are also used for varying the height of the top of the slat assembly.

In order that the invention may be more clearly understood, reference will now be made to the accompanying drawings, in which:

Figure l is a front view of a Venetian blind according to this invention with the top of the slat assembly in a lowered position, with the bottom of the slat assembly in a raised position, and with the slats in a position to provide the maximum passage of light through the slat assembly,

Figure 2 is a section taken on the line AA in Figure l, and on an enlarged scale,

Figure 3 is a fragmentary plan view of the head bar showing the arrangement of the guide pulleys and cords,

Figure 4 is a section along the line BB in Figure 3,

Figure 5 is a fragmentary plan view of an alternative by arrangement of pulleys on the head bar,

Figure 6 is a section along the line C-C in Figure 5,

Figure 7 is a fragmentary plan view of a further modified arrangement of the pulleys on the head board, and

Figure 8 is a section along the line D-D in Figure 7.

Referring to Figures 1 to 4 of the drawings, 1 indicates the frame of the window or other opening across the top of which is fixed the head bar 2 of the Venetian blind. Suspended below the head bar is a slat assembly consisting of a number of thin slats 4 and a bottom crossbar 3, preferably of heavier cross-section than the thin slats 4, the slats being suspended by two tape sets 5 comprising front and rear tapes 5a, 5b interconnected by cross portions 6 for supporting the slats. The upper ends of the tapes 5a, 5b of each tape set are secured to the upper slat 4 whilst the lower ends of the front and rear tapes 5a, Sb of each tape set are secured to the bottom crossbar 3.

Attached to the crossbar 3 between the front rear tapes nited States Patent 0 ice 5a, 5b of each tape set are two elevating cords 7 and 8 which pass vertically upwards from the crossbar 3, through transverse slots 9 in the slats 4 and holes 10 in cross portions 6 of the tape sets and then through holes 11 in the head bar 2, over inner guide pulleys 12 and 13, along the top of the head bar, around appropriately placed guide posts 14, over a double-sheaved outer guide pulley 15 and down through the hole 16 in the head bar 2 in the lower end of which is located a catch 17 of the conventional pivoted dog type for engaging and holding the cords in an adjusted position in known manner. The free ends of the cords 7, 8 hang downwardly at the side of the head bar and are bound together, for example by a knot or a metal band 18, at a point on the cords which remains below the head bar 2 even when the crossbar 3 is lowered to its lowest level.

The weight of the crossbar 3 and any slats 4 which may be resting upon it will normally exert a pull on the cords 7, 8 tending to raise their downwardly hanging free ends. Such movement is normally prevented by the catch 17 which by manipulating the cords can, in known manner, be caused to release to permit the free ends of the cords 7, 8 to be raised under the weight of the crossbar and the slats to lower the crossbar 3. By pulling the free ends of the elevating cords 7, 8 downwardly, the crossbar 3 and the slats can be raised, the crossbar being retained in the adjusted position by the catch 17. The raising and lowering of the bottom crossbar and the slats can be effected in this way without changing the tilt of the slats or the height of the top slat of the assembly.

The top slat 4 of the assembly is supported by two pairs of tilting cords, one pair, the front tilting cords 19 and 20, being secured in holes 21 in the top slat near its front edge, and the other pair, the rear tilting cords 22 and 23, being secured in holes 24 in the top slat near its rear edge. The tilting cords 19, 20, 22 and 23 pass upwardly through appropriately positioned holes 26 in the head bar 2, over inner guide pulleys 27, 28, 29 and 30 respectively, along the top of the head bar, around appropriately placed guide posts 14, in pairs over two double-sheaved outer guide pulleys 31 and 32, and downwardly through the hole 33 in the head bar, the downwardly hanging free ends of the tilting cords being joined together in pairs, for example by knots or metal bands 18a, at points on the cords which are spaced below the head board. The front tilting cords are joined together in one pair and the rear tilting cords are joined together in another pair.

The two double-sheaved guide pulleys 31, 32 are coupled together by gear wheels 34, 35 so as normally to rotate in opposite direction about their axles 37, 38. The sheaves are sharply grooved and may have the groove sides roughened, so as to prevent the cords from slipping in the grooves of the sheaves. It will be seen that, with this arrangement, if the free ends of the front pair of tilting cords l9 and 20 are pulled downwards the front edge of the uppermost slat 4 and consequently the front tapes 5a of the slat assembly will be pulled upwards, and simultaneously, by reason of the pulleys 31 and 32 being geared together for rotation in opposite directions, the pair of rear tilting cords 22, 23 will be moved in a direction to lower the rear edge of the top slat of the rear tapes 5b. The slat assembly is thus tilted without affecting the adjusted height of the top slat or of the bottom crossbar 3. By pulling downwardly on the ends of the rear tilting cords 22 and 23, the slat assembly will likewise be tilted in the reverse direction.

The two pairs of tilting cords are additionally employed for raising and lowering the upper slat and thus the height of the top of the slat assembly. This is achieved by providing means for uncoupling the gearing which interconnects the two double-sheaved pulleys 31 and 32, thus permitting them both to rotate in the same direction and thereby enabling the two pairs of tilting cords to be moved together in the same direction to raise and lower the upper slat. By pulling the free ends of the tilting cords downwardly, the top of the slat assembly may be raised, and vice versa. The upper slat is retained at its adjusted height by re-engaging the gears 34, interconnecting the pulleys 31 and 32.

Thus when the gears 34, 35 are disengaged, the tilting cords can be moved simultaneously in the same direction to adjust the height of the top of the slat assembly and when the gears are engaged the pairs of tilting cords move in opposite directions to efl'ect tilting of the slats without altering the adjusted height of the top slat. The engagement and disengagement of the gears may be effected by manipulation of the tilting cords or by a separate operating member.

According to the embodiment of Figures 1 to 4, the axle 37 of the double-sheaved pulley 31 and its associated gear wheel 34 is mounted in a bearing in the form of a slot 39, whereby the axle 37 may be moved along the slot 39 to a position in which the gear wheel 34 is disengaged from the gear wheel 35. The bearing slot 39 may be slightly inclined to the horizontal so that the pulley 31 normally moves under gravity to a position in which the gear wheel 34 engages with the gear wheel 35. Alternatively or additionally a spring 40 may be provided for urging the axle 37 into the position in which the gear wheels engage. By pulling the hanging free ends of both pairs of tilting cords (or at least of the front tilting cords 19 and 20) inwardly towards the centre of the window as shown by the dotted line position in Figure 1, the axle 37 will be moved in the slot 39 to disengage the gear wheels and allow the tilting cords to be moved together to raise or lower the upper slat. When the cords are released the gear wheels re-engage to retain the top slat at the adjusted height. The mechanism is preferably so constructed that when the tilting cords are pulled vertically downwards the applied force transferred to the pulleys is insufficient to disengage the gear wheels, while when the cords are pulled in the appropriately slanting position the applied force will disengage the gears by overcoming the force tending to hold the gears engaged.

An alternative embodiment is illustrated in Figures 5 and 6 in which the two double-sheaved pulleys 31, 32 are mounted coaxially on the axle 37a and their associated gear wheels 34, 35 are interconnected by the idler gear 36 mounted on a spindle 44 which is slidable axially in its bearing against the action of springs 47 to disengage the idler gear 36 from the gear wheels 34 and 35. The springs 47 bear against a disc 46 secured on the spindle 44, and between the other side of the disc 46 and the wall of the opening in the head bar 2 in which the disc is located is arranged a wire loop 43 the top of which extends above the spindle 44 and the lower end of which pivotally connects with the end of an L-shaped lever 41 pivoted for rocking movement about the axle 38. By rocking the lever 41 in the anti-clockwise direction (looking at Figure 5) the wire loop 43 rocks about the lower edge of the wall of the opening 45 to move the disc 46 towards the left to disengage the gear 36. This movement may be efiected by inclining the tilting cords inwardly towards the centre of the window, to which end the lever 41 is provided with projecting pins 42 which are engaged by the tilting cords when so inclined to rock the lever 41 in the anti-clockwise direction.

Additionally or alternatively a separate cord 48 may be attached to the lever 41, pulling on this cord effecting the swinging of the lever 41.

In the further embodiment illustrated in Figures 7 and 8, the two pairs of tilting cords 19, 20, 22, 23 engage respectively with diametrically opposed parts of the sheaves of a double-sheaved pulley 50 mounted for rotation about a vertical axle 51 on the head bar 2. The

sheaves are sharply grooved, and may be roughened, and the cords are held in frictional engagement in the grooves of the sheaves by pairs of pressure rollers 52, 52a, mounted on arms 53, 53a pivoted at 54, 54a to the head bar 2, the opposite ends of the arms being provided with slots 55, 55a engaged by pins 56, 56a at one end of a lever 51 which is mounted for rocking movement about a horizontal pivot 58. The other end of the lever 51 is formed with a loop portion 59 through which pass the free ends of the tilting cords 19, 20, 22, 23 which extend over the freely moving guide pulleys 60 after leaving the pulley 50. A spring 61 normally urges the lever 57 in a direction to force the pins 56, 56a away from the outer ends of the slats 55, 55a, thereby to urge the pressure rollers 52, 52a together to hold the tilting cords in good frictional contact with the grooves in the pulley 50. Thus, normally, when pulling on the front pair of tilting cords, the consequent rotation of the pulley 50 will cause movement of the rear pair of tilting cords to move in the opposite direction, thereby tilting the slats. By moving the hanging free ends of the tilting cords inwardly towards the centre of the window, they engage the inner part of the loop portion 59 to cause the lever 57 to tilt and move the pins 56, 56a towards the outer ends of the slots 55, 55a, thereby opening the pressure rollers 52, 52a and relieving the friction between the tilting cords and the pulley 50 so as to permit both pairs of tilting cords to be moved simultaneously in the same direction to raise or lower the top slat.

H Whilst particular embodiments have been described, it will be understood that various modifications may be made without departing from the scope of the invention as defined by the appended claims. For example, pressure rollers may be associated with the pulleys 31 and 32 of the embodiments shown in Figures 1 to 6 to ensure good frictional engagement between the tilting cords and the pulleys.

This application is a continuation in part of my application Serial No. 382,319 filed September 25, 1953, now abandoned.

I claim:

1. A Venetian blind comprising a head bar to be fixed to a window frame, a slat assembly comprising a plurality of slats assembled together by at least two tape sets each comprising front and rear upright tapes and cross portions supporting the slats, two elevating cords each connected to the lowermost slat and extending upwardly therefrom and over guides carried by the head bar, said two elevating cords being operable to effect raising and lowering of said lowermost slat to adjust the height of the bottom of the slat assembly, two pairs of tilting cords, one pair being connected to support the upper ends of the front tapes of said two tape sets and the other pair being connected to support the upper ends of the rear tapes of said two tape sets. said tilting cords extending upwardly from said upper ends of the tapes and over guides carried by the head bar, means interconnecting said two pairs of tilting cords so that movement of one pair in one direction will cause simultaneous movement of the other pair of tilting cords in the opposite direction whereby, by pulling on one pair of cords the slats will be tilted by raising one of the front and rear tapes of each tape set and simultaneously lowering the other of said rear and front tapes, and means for uncoupling said interconnecting means to permit said two pairs of tilting cords to be moved simultaneously in the same direction. whereby to effect lowering and raising of the upper ends of all the front and rear tapes simultaneously to adjust the height of the top of the slat assembly.

2. A Venetian blind as claimed in claim 1, comprising two pulleys with which said two pairs of tilting cords respectively engage, gears interconnecting said pulleys for simultaneous rotation in opposite directions, and means for disengaging said gears.

3. A Venetian blind as claimed in claim 2, wherein at least one of said pulleys is mounted for movement in a direction to disengage said gears, and means for normally urging said gears into engagement.

4. A Venetian blind as claimed in claim 2, wherein said gears comprise two gear wheels mounted respectively for rotation coaxially with said two pulleys, an idler gear interconnecting said two gear wheels, and means for moving said idler gear out of engagement with at least one of said gear wheels.

5. A Venetian blind as claimed in claim 4, wherein said idler gear is urged into engagement with said gear wheels by a spring, a pivoted lever being provided for moving said idler gear against the action of said spring.

6. A Venetian blind as claimed in claim 5, wherein said pivoted lever includes a part adapted to be engaged by portions of the tilting cords when the latter are pulled to an inclined position towards the centre of the blind, whereby to efiect movement of the lever to disengage the idler gear.

7. A Venetian blind as claimed in claim 1, wherein the 20 interconnecting means comprises a pulley with which the pairs of tilting cords engage respectively at substantially diametrically opposed parts, members for urging said cords into driving contact with said diametrically opposed parts of the pulley, and means for releasing at least one of said members to permit both pairs of cords to be moved in the same direction.

8. A Venetian blind as claimed in claim 7, wherein said members comprise pressure rollers, a pivoted lever connected to move said pressure rollers towards and away from the pulley, a spring acting on said lever and normally moving the lever to a position to urge the pressure rollers towards the pulley.

9. A Venetian blind as claimed in claim 8, wherein said lever includes cord-engaging parts adapted to be engaged and moved by the tilting cords when the latter are pulled to an inclined position towards the centre of the blind, such movement of the lever moving the pressure rollers away from the pulley.

Kwon May 19, 1942 Kwon Oct. 22, 1946 

